Field of the Invention
The present invention relates to a liquid treatment method, a substrate processing apparatus, and a non-transitory storage medium.
Description of Related Art
For fine processing of substrates, photolithography is now commonly used to form uneven patterns (e.g., resist patterns) on each substrate such as a semiconductor wafer. Various processing liquids are discharged through a discharging port of a liquid nozzle, toward the surface of the substrate, to conduct the fine processing of the substrate.
In a case where a processing liquid is discharged through the discharging port of the liquid nozzle, if liquid is suspended from the end discharging port or if liquid droplets adhere to the surfaces around the discharging port, such liquid may fall onto the surface of the substrate during the discharge of the processing liquid and is thus likely to cause defects. In order to address such problem, the substrate processing apparatus described in Japanese Patent No. JP5045218B2 (corresponding to JP2008-135679A) includes means for imaging a discharging port of a liquid nozzle, means for judging based on the imaging result by the imaging means whether suspending or falling of the processing liquid from the discharging port, and means for controlling a liquid nozzle transport mechanism to perform a predetermined operation for coping with the suspending or falling of the processing liquid. The substrate processing apparatus of JP5045218B2 thus can prevent occurrence of an abnormality of processed substrate.
The substrate processing apparatus described in JP5045218B2 judges the occurrence of the suspending of the processing liquid upon comparison of a suspending degree indicator value with a predetermined threshold. If the threshold is not set appropriately, even if a small amount of liquid suspending occurs, the judging means may judge that unallowable liquid suspending or liquid falling occurs, resulting in unnecessary execution of the predetermined operation for coping with the abnormality; or even if a large amount of liquid suspending occurs, the judging means may judge that unallowable liquid suspending or liquid falling does not occur, resulting in failure of execution of the predetermined operation.